Roll stands having a plurality of rolls, which are designed and disposed such that they form a roll pass for rolling rod-shaped or tubular shaped rolling material, are known in multiple designs. The roll stands are disposed in a roll stand receptacle in a rolling line. Changes in the dimensions of the rolled product or a change of the rolls as a result of damage or wear makes it necessary to change one or a plurality of roll stands and to replace those stands with others.
Previously known roll stand changing devices can essentially be categorized into four types.
In a first group, a roll stand changing cart receives a roll stand, travels with this roll stand (transverse to the direction of rolling) in the rolling line and remains in the rolling line during rolling. The roll stand changing cart and roll stand thereby form a unit. A fixed number of roll stands are thus allocated to a roll stand changing cart. In the case of this group of roll stand changing devices, it is not possible to pull individual roll stands out of the rolling line while the remaining roll stands remain in the rolling line.
In the case of an additional group, the roll stand receptacle of the rolling block is opened at the top and the roll stand can be inserted into the rolling block from above or lifted upward out of this rolling block with the help of a special crane or manipulator. This design is very costly and in addition, the rolling line is generally inaccessible, which is a great disadvantage with regard to serviceability.
According to a third known group, a roll stand is inserted or removed laterally, i.e. transversely to the direction of rolling, in a horizontal direction from the roll stand changing cart down into in what is referred to as the roll stand receptacle of the rolling block. A separate displacement mechanism may be provided for each roll stand so that, depending on the operator's wishes, either individual roll stands or all of the roll stands together can be displaced from the rolling block onto the roll stand changing cart or from the roll stand changing cart into the rolling block. The known displacement mechanism is disposed either on the side of the roll stand that is facing away from the operating side, or in other words the so-called drive side, or on the operating side. The configuration of the displacement mechanisms on the drive side has the disadvantage that the available installation space is extremely limited due to other components that are disposed here, as a result of which the displacement path that must be achieved is very small. In addition, any maintenance work that is needed is costly and inconvenient to perform. Insofar as the displacement mechanism is disposed on the operating side, two different designs are known. On the one hand, the displacement mechanisms may be disposed on the operating side of the rolling block, on the other side of the roll stand changing cart. The roll stand changing cart is thus located between the rolling block and the displacement mechanism. Inevitably, the result is that the roll stand changing cart can only travel parallel to the rolling line, but not transverse to the rolling line away from the rolling block directly into the roll stand workshop. This can lead to serious disadvantages, which are dependent on the existing layout of the respective roll train. Among other things, it may be provided that the displacement mechanisms are disposed on the roll stand changing cart itself. In this case, this results in the disadvantage that at least twice the number of the roll stand displacement mechanisms must be provided, since there are always at least two roll stand changing carts present.
As an alternative to the option of providing a separate displacement mechanism for each roll stand, it is also possible to move the roll stands of the rolling block with the help of a so-called changing beam, which extends along the length of the rolling block. The result of this is that, for technical reasons, it is not possible to dispose the changing beam on the drive side, since, as a result, the roll stands cannot be moved individually, but rather, can only be moved collectively on the rolling block.
In the case that the changing beam is disposed on the operating side of the roll stand, a distinction can be made between three designs. In the case of the first design, the changing beam and the drive thereof are disposed on the operating side, on the other side of the changing beam. The result is the already known disadvantage that the roll stand changing cart cannot travel directly with the roll stands (transverse to the rolling line) into the roll stand workshop. In a second design, the changing beam and the drive therefor are disposed on the roll stand changing cart. This design has the disadvantage that two roll stand displacement units must be provided, since at least two roll stand changing carts are needed in order to quickly exchange a roll stand. In a third design, the changing beam is disposed on the roll stand changing cart, while the displacement drive, on the other hand, is displaced on the side of the rolling block. This design has the advantage that only the changing beam must be implemented twice, however the associated drive need only be implemented once. In the case of the latter design, the roll stand changing carts can travel directly, transversely to the rolling line, into the roll stand workshop. The disadvantage, however, is that the displacement unit must make a number of empty trips in order to connect to the changing beam located on the roll stand changing cart before displacing the roll stand, and in order to disconnect from the changing beam and return to the starting position after the displacement of the roll stand. Furthermore, the required coupling mechanism results in a cost disadvantage.
In the fourth group of roll stand changing devices, the devices are moved out of the rolling block, either in the direction of rolling or against the direction of rolling.
The primary disadvantage of this so-called tunnel solution is that a displaceable roller table must be disposed either in front of or behind the rolling block, in order to create the space to move the device out of the rolling block. Under circumstances, this results in serious disadvantages for the layout of the entire roll train. A special design of this roll frame changing system provides that half of the stand travels out of the block in the direction of rolling, and the other half travels out of the block against the direction of rolling. This increases the technical complexity however, without reducing the overall space requirements.
The changing mechanisms used in the prior art use a displacement element that can be moved in a straight line, which element can be actuated such that it engages with the roll stand, and which must be again disconnected or, respectively, removed therefrom. Purely translational movements are carried out, which must be carried out twice in order to displace the roll stand out of the roll stand receptacle, for example when using the changing beam: one movement for the extension and one movement for a disengagement therefrom.